diff --git a/lib/hexapdf/configuration.rb b/lib/hexapdf/configuration.rb
index 2d791770..b6b2f62b 100644
--- a/lib/hexapdf/configuration.rb
+++ b/lib/hexapdf/configuration.rb
@@ -610,6 +610,7 @@ def constantize(name, *keys)
                         PageLabel: 'HexaPDF::Type::PageLabel',
                         XXMarkInformation: 'HexaPDF::Type::MarkInformation',
                         OCG: 'HexaPDF::Type::OptionalContentGroup',
+                        OCMD: 'HexaPDF::Type::OptionalContentMembership',
                         XXOCUsage: 'HexaPDF::Type::OptionalContentGroup::OptionalContentUsage',
                         XXOCUsageCreatorInfo: 'HexaPDF::Type::OptionalContentGroup::OptionalContentUsage::CreatorInfo',
                         XXOCUsageLanguage: 'HexaPDF::Type::OptionalContentGroup::OptionalContentUsage::Language',
diff --git a/lib/hexapdf/type.rb b/lib/hexapdf/type.rb
index 49dc3941..86aedbd8 100644
--- a/lib/hexapdf/type.rb
+++ b/lib/hexapdf/type.rb
@@ -77,6 +77,7 @@ module Type
     autoload(:PageLabel, 'hexapdf/type/page_label')
     autoload(:MarkInformation, 'hexapdf/type/mark_information')
     autoload(:OptionalContentGroup, 'hexapdf/type/optional_content_group')
+    autoload(:OptionalContentMembership, 'hexapdf/type/optional_content_membership')
 
   end
 
diff --git a/lib/hexapdf/type/optional_content_membership.rb b/lib/hexapdf/type/optional_content_membership.rb
new file mode 100644
index 00000000..4431071c
--- /dev/null
+++ b/lib/hexapdf/type/optional_content_membership.rb
@@ -0,0 +1,63 @@
+# -*- encoding: utf-8; frozen_string_literal: true -*-
+#
+#--
+# This file is part of HexaPDF.
+#
+# HexaPDF - A Versatile PDF Creation and Manipulation Library For Ruby
+# Copyright (C) 2014-2023 Thomas Leitner
+#
+# HexaPDF is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License version 3 as
+# published by the Free Software Foundation with the addition of the
+# following permission added to Section 15 as permitted in Section 7(a):
+# FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
+# THOMAS LEITNER, THOMAS LEITNER DISCLAIMS THE WARRANTY OF NON
+# INFRINGEMENT OF THIRD PARTY RIGHTS.
+#
+# HexaPDF is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+# License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with HexaPDF. If not, see <http://www.gnu.org/licenses/>.
+#
+# The interactive user interfaces in modified source and object code
+# versions of HexaPDF must display Appropriate Legal Notices, as required
+# under Section 5 of the GNU Affero General Public License version 3.
+#
+# In accordance with Section 7(b) of the GNU Affero General Public
+# License, a covered work must retain the producer line in every PDF that
+# is created or manipulated using HexaPDF.
+#
+# If the GNU Affero General Public License doesn't fit your need,
+# commercial licenses are available at <https://gettalong.at/hexapdf/>.
+#++
+
+require 'hexapdf/dictionary'
+
+module HexaPDF
+  module Type
+
+    # Represents an optional content membership dictionary.
+    #
+    # A membership dictionary allows more complex visibility policies, like:
+    #
+    # * Content that should be visible when a certain optional content group is off instead of on.
+    # * Content that should be visible when all of a number of OCGs are on.
+    #
+    # See: PDF2.0 s8.11.2.2
+    class OptionalContentMembership < Dictionary
+
+      define_type :OCMD
+
+      define_field :Type, type: Symbol, required: true, default: type
+      define_field :OCGs, type: [:OCG, PDFArray]
+      define_field :P,    type: Symbol, default: :AnyOn,
+        allowed_values: [:AllOn, :AnyOn, :AnyOff, :AllOff]
+      define_field :VE,   type: PDFArray
+
+    end
+
+  end
+end